Dynamips - is an emulator program that was written to emulate Cisco routers. Dynamips runs on Linux , Mac OS X or Windows and can emulate the hardware of the Cisco series routing platforms by directly booting an actual Cisco IOS software image into the emulator.

Dynagen - is a front-end for use with the Dynamips Cisco router emulator. It uses an INI-like configuration file to provision Dynamips emulator networks. It takes care of specifying the right port adapters, generating and matching up those pesky NIO descriptors, specifying bridges, frame-relay, ATM switches, etc. It also provides a management CLI for listing devices, suspending and reloading instances, determining and managing idle-pc values, performing packet captures, etc.